Multiple smoke detector



March 2 1948. c. N. cAHUsAc Er Ax. 2,437,071

MULTIPLE `SMOKE DETECTOR Filed oct. 2, 1945 Patented Mar. 2, 1948 OFFICE g 2,437,071 MULTIPLE sMoKE DETECTOR Clarence Noel Cahusac, Newark, and Frank B. Allen, Verona, N. J., assignors to C-O-Two Fire Equipment Co., Newark, N. J., a corporation of Delaware Application October 2, 1945, Serial No. 619,743

6 Claims. (CI. 177-311) This invention relates to an apparatus for detecting the presence of smoke at some place remote from the location of the apparatus which is'designed to be placed where it can be under continual observation. The apparatus is especially useful in locating the presence of smoke in various parts of a ship. airplane, factory, or warehouse, so that the fire which may get started therein can be detected and immediate steps taken for extinguishing it.

While certain types of apparatus have been proposed and used in the past for smoke detection it is the object of our present invention to provide an improved type of apparatus which will be easier to manufacture and hence less expensive and one which will occupyfless space. Another object of our invention is to provide an improved type of apparatus for the purpose described which is more eiilcient in operation.

Other objects will be discerned by one skilled in this particular art from the reading of the following specication taken in connection with the annexed drawing wherein:

Figure 1 is a plan view of the apparatus.

Figure 2 is a section on the line 2-2 of Figurel.

Figure 3 is a diagram showing electrical connections between one of the control units and certain types of alarm devices.

In the drawing I is a casing preferably and generally circular in form and having a plurality of compartments, six being shown, A-F. These compartments are divided by partitions or Walls 2, and are arranged in an arcuate manner about a central chamber 3. Within the chamber 3 there is provided a source of light in the form of an electric socket I carrying a light bulb 5 of suitable candle power. The chamber 3 has a. plurality of openings 6 therein, one for each compartment, A-F. Directly adjacent each opening 6 there is mounted a lens 'I preferably the double convex type so as to direct a beam 8 of parallel rays of light across its compartment. Preferably the rays of the beam 8 strike a light absorbent pad or body 9 so that no uncontrolled reflections will come from the ends of the beam Vwhere it strikes the periphery of the casing I.

Each compartment has mounted therein a photoelectric cell of the current generating type and While these are all alike they are numbered I0, II, I2, I3, I4, I5. Each photoelectric cell is carried by a support I6 that is adjustably mounted through the medium of screws Ii and 'slots I8 whereby the distance of each cell from the beam 8 may be adjusted as well as the angularity of 2 the cell with respect to the beam as we have found it advantageous to be able to set each cell at a slight angle to its associated beam 8 so as to reduce the possibility of the cell being energized by the stray light rays.

Mounted in the partitions or walls 2 are signal lights I9, 20, 2i, 22, 23 and 24, which are associated in pairs, for example, I9 and 20 as illustrated in Figure 2,- with a signal device 25, such as a Sensitrol relay, that serves to control the production of a warning which may be either audible or visible, or both, of smoke coming from places represented by two of the com partments, respectively. For example, there is one device 25 :fork the two compartments A and B, another for the compartments C and D and another for the compartments E and F. Each compartment is provided with an inlet pipe 2S which leads from the place to be protected, for example, a room in a small factory, to the compartment. The smoke passes through the compartment and through the opening 6 of the chamber 3 which is provided with an outlet pipe 21 that is connected to a suction fan and motor` (not shown) or suitable means for causing the circulation of smoke through the compartment.

It will be noted from Figure 3 that the indieating device 25 has an energizing coil28 which is adapted to move an arm or contact member 29 into engagement with either contact 39 or 3|, depending on the direction ofthe flow of current through the coil 28 and this is governed by the flow of current from the photoelectric cells I0 and II as illustrated. Each cell I0, II, I2. I3, I 4 and I5 is connected in circuit with the other cell, of its pair, e. g. cell I 0 with cell II, and with the corresponding responsive device 25 in what is known as an opposed parallel arrangement; in other words, the electrodes of one cell are connected to the opposite electrodes of the other cell. Thus when no smoke is in the compartments, the effect of stray light rays on one,

cell of the pair can be balanced by the eiect of light rays on the other cell, whereby a steadyl smoke come into one of the compartments containing the photoelectric cells I or li then the other cell will energize the coil 28 to close a circuit from a source of current S by way of the pointer 29v and one of the contacts 30 and 3|. I! the contact 30 is the one that is closed then the lamp i8 will light and audible signals of dif. ferent character may be given by the devices 32 and 33 associated with the lamp I9. If the contact .1I be closed. then the lamp 20 will light and audible signals be given by the devices 3l and 35 which may be of any desirable type.

From what has been said it will be seen that one of the indicators 25 takes care oi' two of the compartments so that for the six compartments illustrated only three indicating instruments are necessary: and the photoelectric cells of each pair operate in compensating, differential or opposing relation. It is thus possible to provide a compact photoelectric apparatus for detecting smoke fromv a plurality of zones to be protected. with the utilization of a minimum number of electrical responsive devices and photoelectric cells.

It will also be noted that the air drawn through all of the compartments constantly contacts with and cools the lamp 5.

While we have shown six compartments it will be understood that the number of compartments may be anv nurober desired. and the shape there oi' varied from that illustrated but we have found that where the compartments are arranged in the form oi' sectors, a very compact construction is obtained. y

Having thus described a present form of our invention. what we claim is:

1. Apparatus for the purpose described comprising, a casing having a plurality of compart- 'i ments with dividingajralla arcuately arranged around a centrally located chamber, each compartment having an inlet for air and smoke and an outlet to said chamber, a source of light in said chamber, the chamber having an outlet for air and smoke and openings into each compartment whereby light rays from said source may pass through said openings into each compartment, a lens mounted in alignment with each opening to direct a beam of light across its compartment, a current generating photo-electric cell for each compartment and mounted therein in operative relationship to the beam light therein, an indicating instrument mol. ;ed in the wall between two adjacent compartments and having an actuating coil connected across the series connecting leads joining the photoelectric cells of said adjacent compartments, said instrument having a movable member responsive to current from one oi' said cells with a pair oi' oppositely disposed cooperating contacts each connected to an alarm device.

2. Apparatus as set forth in claim 1 further characterized in that each lens is mounted closely adjacent its cooperative opening in the chamber, while said openings also serve to pass said air and smoke from the compartment containing it to the chamber, the chamber having a discharge duct leading therefrom. v

3. Apparatus for the purpose described comprising a circular casing having a centrally located chamber with an exit pipe connected thereto and also having sector shaped compartments surrounding the chamber, each compartment having, adjustably mounted therein a current generating photoelectric cell and an incoming pipe from a place to be protected, the chamber having a source of iight therein and openings into each compartment to at least let the light thereinto. a lens for each compartment mounted to receive the light and direct a beam across the compartment adjacent the cell with means at the outer extremity oi' the beam to prevent reflection of the light and an indicating instrument having an operating coil connected across the series arrangements of the cells of two compartments said instrument having a movable member responsive to current from one of said cells with a pair of oppositely disposed cooperating contacts each connected to an alarm device.

4. Smoke detecting apparatus comprising a casing having a plurality oi separate compartments each having a conduit leading thereto from one zone or section from which smoke is to be derived, a chamber having an outlet conduit' and also having an opening into each compartment, a source oi.' light in said chamber positioned to send light through each oi' said openings across its compartment with means for insuring that the light travels in substantially straight lines, a current generating photoelectric cell in each compartment mounted so as to receive a suitable amount of light from its cooperative beam, an indicating instrument having an actuating coil connected across the series connecting leads joining the cells of two compartments, said instrument having a movable member responsive to current through said coil from one of said cells, contacts adapted to be engaged by said movable member to close a circuit from a source of current. through a signal device associated with the compartment that receives the smoke.

5.` Smoke detecting apparatus comprising a casing having a plurality of separate compartments, each having a conduit leading thereto from one zone or section from which smoke is to bev derived, a chamber communicating with each compartment and having an outlet for smoke from all of said compartments, a source ot light in said chamber, said chamber having an opening into each compartment through which light from said source is projected across the corresponding compartment with means for ensuring that the light travels in substantially straight lines, a current generating photoelectric cell in each compartment mounted so that light will be reflected from suspended matter in said smoke upon the corresponding photoelectric elements, means connecting said photoelectric elements in an electric circuit whereby the photoelectric effects of one o! said elements opposes the photoelectric eects of another of said elements, and an electrical responsive means in said circuit and actuated by electricity generated by said photoelectric elements.

6. Apparatus for the purposes described, comprising a casing having a plurality of compartments surrounding a centrally located chamber,

each compartment having an inlet for air and l smoke and an outlet to said chamber, and said chamber having a common outlet for smoke from all of said compartments, a source of light, and means for directing a beam of light from said source through each of said openings across the corresponding compartment, a current generating photoelectric cell for each compartment and mounted therein in operative relationship to the beam of light-therein, a plurality of indicating instruments each common to two compartments and having an actuating coil connected across the series connecting leads joining the photoelec- REFERENCES CITED tric cells of said two compartments. said instruments having a movablel member responsive to The following references are of record in the current from one of said cells with a pair of ie of this patent: oppositely disposed cooperating contacts, each 5 connectedtoan am device UNITED STATES PATENTS Number Name Date CLARENCE NOEL CAHUSAC. 878.456 Darwin Feb. 4, 1908 FRANK B. ALLEN. 2,301,367 Cahllsac et al. Nov. 10. 1942 

